This study involves the treatment of IgA nephropathy. IgA nephropathy is a disorder of the filters of the kidney. Each kidney has many little filters that filter the waste products out of the blood and into the urine, leaving important substances like proteins in the blood. In IgA nephropathy, a substance called IgA gets stuck in the filters, and they let protein out of the blood and into the urine. They may or may not filter the waste products out of the blood like they should. We hope to learn if either of two treatments are better than no treatments in slowing the damage to your kidneys from IgA nephropathy. Patients will receive one of three treatments: alternate day prednisone with decreasing dose, fish oil, or placebo. It is two years with treatments and three years follow-up.